Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true and readOnlyHint=false, so the description's 'update' is consistent but adds little beyond the requirement for Id and SyncToken. It does not disclose sparse update behavior or line replacement, which are relegated to schema description. No contradiction; limited added value.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, efficient sentence that front-loads the core action and essential requirement. It is appropriately concise with no wasted words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description is minimal but adequate given the rich schema description for the entity parameter. It covers the core 'what' and the precondition, but does not mention important behavioral nuances like sparse vs full updates, which are only in the schema. Since no output schema exists, return value expectations are unaddressed, though not explicitly required.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, with detailed descriptions for both entity and company parameters. The tool description adds no parameter meaning beyond restating the Id and SyncToken requirement already present in the schema. Baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description explicitly states the verb 'update', the resource 'refund receipt', and qualifies it as 'existing', which clearly distinguishes it from create or get tools. It also adds the requirement of Id and SyncToken, making the purpose unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives context (existing refund receipt, requires Id and SyncToken) but does not mention alternatives or when not to use it. It implies update vs create but doesn't explicitly say 'use create_refund_receipt for new receipts', leaving selection partially to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.